[x300] Catalytic converter

X300
1

My 1995 XJ6 just failed a second smog test, right after getting
some minor engine repairs. Turns out both catalytic converters are
bad. I was told by the repair shop that they could not find any
converters other than going to a Jaguar dealer, and the cost was
$2500 for front one and $2700 for the back one. This is California
by the way. The repair folks said they couldn’t find any after-
market cc’s for California. I now have an appointment with the
smog referee to see if I can get a smog waiver. If I get the
waiver I have 2 years to pass smog test. Otherwise Jag has to be
retired, or donated. Know where I can find California cc’s that
are reasonably priced?

Thanks–
jimemac 1995 XJ6
South San Francisco, CA, United States
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2

In reply to a message from jimemac sent Fri 9 Sep 2011:

A quick answer - At a junk yard/ Try Coventry West- They are sorta
high $, but they have most things. Other than that, just get on
a ‘‘used car part’’ network.–
Ross - 89 XJS, 98 XJR, 99 XJR, 02 XJ8
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3

In reply to a message from jimemac sent Fri 9 Sep 2011:

NOthing wrong with the catylic converters! what were the figures
for the nox hc co2 and o2? Better take it to someone who is
reputable (all this is moot if the casings are rotted off and the
exhaust is loud) What is the mileage on the car?–
Rlysmthn '96 VDP Black/ OM Los Angeles '80 QP x2
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4

In reply to a message from jimemac sent Fri 9 Sep 2011:

California does not allow the sale of used catylic converters, it
is against the law in the state. I had my first smog li9cense in
1966 and stayed current unti9l a few years ago–
Rlysmthn '96 VDP Black/ OM Los Angeles '80 QP x2
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5

In reply to a message from jimemac sent Fri 9 Sep 2011:

Hello,

I endorse what a previous member has said - check your 02 sensors
first. I failed an emissions test in the UK and I too was advised
to get new catalytic converters. Thanks to the advice given by
members of this forum I identified the cause of the fault as one of
the 02 sensors, I changed it and the car then passed its emissions
test.

Good Luck–
The original message included these comments:

My 1995 XJ6 just failed a second smog test, right after getting

–
rm21355y
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6

In reply to a message from rlysmthn sent Fri 9 Sep 2011:

Why are you saying there is nothing wrong with the catalytic
converters? You don’t think the shop I took the car to was
reputable? I must be misunderstanding something.

Thanks–
The original message included these comments:

NOthing wrong with the catylic converters! what were the figures
for the nox hc co2 and o2? Better take it to someone who is
reputable (all this is moot if the casings are rotted off and the

–
jimemac 1995 XJ6
South San Francisco, CA, United States
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7

In reply to a message from rm21355y sent Fri 9 Sep 2011:

What test can I do to validate that the )2 sensors are OK.
Would bad 02 sensors cause a heat buildup from under car.

Thanks–
The original message included these comments:

I endorse what a previous member has said - check your 02 sensors
first. I failed an emissions test in the UK and I too was advised

–
jimemac 1995 XJ6
South San Francisco, CA, United States
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8

In reply to a message from jimemac sent Sat 10 Sep 2011:

jimemac- I suppose that is your name?- Many of us use our first
names here, but that’s uop to you.
I believe the remark about a reputable shop is because there are
seldom actual reports of X-300 cats actually going bad. The OBD
low cat performance code is frequently set by a bad o2 sensor or
some other problem with the engine.

I did not offer my opinion originally, because you just asked where
to get catalytic converters, not what we thought might be wrong/

From your post, it sounds like the car actually failed on real
emmisions, asd measured, rather than on a code. Do you have a
check engine light? What codes? Any stored codes?. I have heard
that the Peoples Republic of California does not allow AutoZone or
other parts outlets read codes- It is allowed in the still free
states. If no codes, what failed the car? Was it NOx or CO?

And, YES, as a matter of fact, if the car is running rich, the cats
can be burning the excess fuel and can get quite hot. And that can
come from bad sensors. BTW, O2 sensor failures are rare for these
cars, too, but more often that cats.

Good luck. There is actually a good bit of good technical info on
this biard for X-300s (the fancy name for a MY 95 thru MY 97 XJ6).
Probably as much or more than many Jag shops which work on a large
variety of models.

Bad O2 sensors are diagnosed by using an OBD scanner, or even an
oscilloscope and monitoring the sensor voltage while the car is
running. Most of the time, a bad sensor will ‘‘throw a code’’ and
turn on the ‘‘check engine’’ light.

Have I explained any of this well enough to make sense so far?

And… good luck. Please keep us posted with any results.–
Ross - 89 XJS, 98 XJR, 99 XJR, 02 XJ8
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9

In reply to a message from sparkenzap sent Sat 10 Sep 2011:

Ross - Thanks for that information. Yes, I did not originally ask
for a diagnosis over the forum, or ask if everyone thought my
repair shop was reputable :). I do appreciate the feedback
regarding the problem with the cats and 02 sensor though.

The history - took car in for oil change and emission test a week
ago. Emiision test failed due to HC (PPM) MEAS = 196(15 mph) and
47 (25 mph), and CO (%) MEAS 0.17 (15 mph) and 0.16 (25 mph).

Took car to repair shop which first fixed various oil leaks, which
I new I needed done. Here is their inspection report:
1 - scanned computer, no trouble codes stored.
2 - Checked fuel pressure, good at 36 psi.
3 - checked plugs, worn and oil soaked (changed 30,000 miles ago).
4 - checked air filyer dirty.
5 - checked catalytic converter efficiency, converters about 100
degrees hotter at rear, should be 150 degrees hotter at rear.

After mini tuneup and fixing oil leaks still failed emissions:
HC (PPM) MEAS = 213 (15 mph) and 78 (25 mph), CO (%) 0.27 925 mph)
and 0.20 (25 mph).

Car is a 1995 XJ6 with 122,000 miles on it.

Thanks
Jim–
jimemac 1995 XJ6
South San Francisco, CA, United States
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10

In reply to a message from jimemac sent Sat 10 Sep 2011:

Jim:
I don’t know the California limits, but it looks like you got worse
for your second test-

If you have no codes, and the service guy scanned the sensors, I
assume he would have checked that they were cycling correctly.
ASSUMING he did, you might very well hane bad cats.

The test for O2 sensors is to watch to see them cyle high to low
and back at a rate of about 1 to 2 seconds. The funny thing is
that most of us get codes before the emmisions test will fail. But
maybe California’s test is more stringent. My car is ar rhe office
with the test results inside, so I can’r say what my numbers are.
I occaisonally get low cat efficiency codes, but pass the test
easily every year.

You know, getting the car over to Nevada for a quick vacation might
be just what it needs to clear up its codes- maybe find someone
to ‘‘look’’ at the cats while you were there.–
Ross - 89 XJS, 98 XJR, 99 XJR, 02 XJ8
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11

In reply to a message from sparkenzap sent Sat 10 Sep 2011:

Ross - I think the California test is more strict than the other
states. When I was looking for after-market cats all I could find
where cats for 49 states, not Californiaa. I think I may try to
get the sensors tested just to be certain. If I don’t get the smog
waiver or get the emission test to pass by the end of the month,
the car is history.

Thanks
Jim–
jimemac 1995 XJ6
South San Francisco, CA, United States
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12

In reply to a message from sparkenzap sent Sat 10 Sep 2011:

I may need to get over to Nevada. I feel like I could use some
time at the tables :).

Thanks
Jim–
The original message included these comments:

You know, getting the car over to Nevada for a quick vacation might
be just what it needs to clear up its codes- maybe find someone
to ‘‘look’’ at the cats while you were there.

–
jimemac 1995 XJ6
South San Francisco, CA, United States
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13

In reply to a message from jimemac sent Fri 9 Sep 2011:

How old/what grade is your gas?

I had a car sitting for a few months. Got it started back
up and took it in for a safety inspection. Measured
emissions were astronomically high. The guy that tested it
came back and said ‘‘Man, how old is your gas? That’s the
only thing that ever makes the numbers this high.’’

Sure enough, he was right. I completely drained the old
stuff out of the tank with a siphon. Put in 5 gallons of
premium high octane and ran it out. Did that two more times.
(That way any residual impurities were only diluted in 5
gallons and I only had to run 5 gallons out instead of a
whole tank.) Then, filled the tank with premium, took it
back in, and passed with flying colors.

By the way, I was also told I could try a fuel additive to
help get some of the water and other stuff out of the tank
while I was trying to run it dry, but to run and fuel with
additives out completely and NOT to add an additive to the
tank when I went back for the inspection because some
additives can cause funky results. Can’t confirm any of
that, but I thought I’d pass it along just in case.–
'96 VDP 4.0, '95 XJ6 4.0, and '96 XJS 4.0
Dallas, Texas, United States
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14

Hi @jimemac

I’ve got a 95 X-300 with 115,000 on it. Same problems as this poster. I thought i’d jump in here right quick on his thread.
I’m in California and just can’t deal with it any longer. Can’t smog the Jag. :frowning:
I’m ready to go to Nevada and or Wyoming. I have a relative in Wyoming.
For the sake of getting the Cat. Converters “looked at”.
Suggestions as to places in Nevada? :slight_smile:
Thx,
Tim